/usr/share/doc/asterisk/changelog.Debian.gz is in asterisk 1:13.18.3~dfsg-1ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/asterisk/../asterisk-modules/changelog.Debian.gz
/usr/share/doc/asterisk/../asterisk-modules/changelog.Debian.gz